Thomson received his education at Harrow School, a privately funded public school in the Harrow district of London.
After Harrow, Thomson was accepted to and enrolled at Pembroke College, Oxford in 1815. After a year Thomson left Pembroke because he found that its science departments were lacking courses of interest to him. To sate his scientific appetite, George transferred to St. John's College at Cambridge in 1816. Also, during this year Thomson "acquired the additional name Poulett, which his father had recently adopted from an earlier and aristocratic branch of his family. "
Once at St. John's, Thomson was introduced to Professors Edward Daniel Clarke and Adam Sedgwick who "gave him his lifelong interest in geology. " At the time these men were in the early stages of their careers, Clarke having been made the first professor of mineralogy within the field of geology at St. John's and Sedgwick who was known for his attention to detail and his naming of certain sections of the geologic time scale including the Cambrian. Thomson received his Bachelor of Arts degree in 1821 in geology, after having performed several years of field work in continental Europe.
During the winter of 1816-1817 he was at Naples, and was so keenly interested in Vesuvius that he renewed his studies of the volcano in 1818; and in the following year visited Etna and the Lipari Islands.
He entered parliament in 1833 as M. P. for Stroud, retaining his seat until 1868. Meanwhile he began to study the volcanic regions of Central France in 1821, and visited the Eifel district in 1823. In 1825 he published Considerations on Volcanos, leading to the establishment of a new theory of the Earth, and in the following year was elected F. R. S. This earlier work was subsequently amplified and issued under the title of Volcanos (1862): an authoritative text-book of which a second edition was published ten years later. In 1827 he issued his classic Memoir on the Geology of Central France, including the Volcanic formations of Auvergne, the Velay and the Vivarais, a quarto volume illustrated by maps and plates. The substance of this was reproduced in a revised and somewhat more popular form in The Geology and extinct Volcanos of Central France (1858). Among his other works was the History of the Manor and AncientBarony of Castle Combe (printed for private circulation, 1852).
"Geologists have usually had recourse for the explanation of these changes to the supposition of sundry violent and extraordinary catastrophes, cataclysms, or general revolutions having occurred in the physical state of the earth's surface.
As the idea imparted by the term Cataclysm, Catastrophe, or Revolution, is extremely vague, and may comprehend any thing you choose to imagine, it answers for the time very well as an explanation; that is, it stops further inquiry. But it also has had the disadvantage of effectually stopping the advance of science, by involving it in obscurity and confusion. "
"It has hitherto been a serious impediment to the progress of knowledge, that is in investigating the origin or causes of natural productions, recourse has generally been had to the examination, both by experiment and reasoning, of what might be rather than what is. The laws or processes of nature we have every reason to believe invariable. Their results from time to time vary, according to the combinations of influential circumstances; but the process remains the same. Like the poet or the painter, the chemist may, and no doubt often' does, create combinations which nature never produced; and the possibility of such and such processes giving rise to such and such results, is no proof whatever that they were ever in natural operation. "
"We cannot see how the evidence afforded by the unquestioned progressive development of organised existence—crowned as it has been by the recent creation of the earth's greatest wonder, MAN, can be set aside, or its seemingly necessary result withheld for a moment. When Mr. Lyell finds, as a witty friend lately reported that there had been found, a silver-spoon in grauwacke, or a locomotive engine in mica-schist, then, but not sooner, shall we enrol ourselves disciples of the Cyclical Theory of Geological formations. "
After a comfortable courtship, George Julius Poulett Thomson was married to Emma Phipps Scrope on 22 March 1821. Emma Phipps was the heiress of William Scrope (phonetically Scroop) of Castle Combe, Wiltshire, which is northeast of Bath and east of Bristol. She was also the great-granddaughter of Sir Robert Long, 6th Baronet. After a Royal Grant he assumed the name and arms of Scrope, in lieu of Thomson.
The newly renamed George Poulett Scrope and his wife resided at Castle Combe Manor House, which the Scrope family had owned since the fourteenth century. Emma had been disabled after a riding accident soon after the marriage, and no children were born of their union.
During the marriage, George Poulett Scrope kept a mistress, an actress known as Mrs. Grey, in a very comfortable existence in London. Around the year 1838 their son was born, whom they called Arthur Hamilton. Scrope sent his illegitimate son to Eton College and Christ Church in Oxford for his education, eventually securing a commission for him. In 1856, Emma and George formally adopted Arthur as their son.
With Emma's death in 1866, Scrope sold Castle Combe and moved to Fairlawn, Surrey. The following year Scrope married Margaret Elizabeth Savage, who was forty-four years his junior. Both Margaret Scrope and Arthur survived him.